The objective of this study is to investigate, as a proof-of-principle, long-term (52 weeks) effects of tirzepatide once-weekly vs. placebo on changes in coronary plaque composition and progression (assessed by NIRS), plaque burden (assessed by IVUS) and microvascular function (assessed by invasively measured CFR) in overweight and obese individuals with stable coronary artery disease (CAD). In addition, the objective of a baseline cross-sectional sub-study is to explore potential metabolic and cardiovascular (CV) predictors for high arteriosclerotic plaque burden in overweight and obese individuals and to establish a cohort for future research projects.